York OPTIVIEW - Section 3: VSD Operation; OptiSpeed Compressor Drive Overview; OptiSpeed Compressor Drive Features

JOHNSON CONTROLS
135
FORM 160.78-O2
ISSUE DATE: 5/22/2017
3
OPTISPEED COMPRESSOR DRIVE
OVERVIEW
The new YORK OptiSpeed Compressor Drive (OSCD)
is specifically designed for the application of driving
a permanent magnet high speed motor with magnetic
bearings used on the YORK Model YMC
2
Centrifugal
Liquid Chiller. This type of design allows the chiller to
be design as a complete system, and take full advantage
of the strengths of each major component within the
system. This method of design is a superior approach
to using general purpose components off the shelf that
may not work well together.
This new OSCD design builds on the successes of pre-
vious designs of being chiller mounted, provide for
high levels of energy savings, great integration with
the chiller control center, liquid cooled, shell and tube
heat exchanger, use of fast switching insulated gate bi-
polar transistors (IGBT’s), high reliability, and ease of
service.
New features include:
• The option of a circuit breaker or disconnect
switch.
• Ground fault detection even when a disconnect
switch is selected.
• Direct liquid cooling.
• A more accessible cooling system.
• Variable voltage input.
• High speed direct drive motor.
• Theharmoniclterisstandardonallmodels.
• Modular lighter weight power units that can be re-
pairedintheeldwithoutcompletereplacement.
• Ease of maintenance.
OPTISPEED COMPRESSOR DRIVE
FEATURES
The new drive design is currently available in the fol-
lowing models: HYP490, HYP0490A and HYP744.
For the first time, the OSCD is offered with a discon-
nect switch without giving up the ability to detect a
ground fault. The OSCD contains 3 input current sen-
sors that will provide the information for the drive log-
ic board to detect a ground fault condition.
Direct liquid cooling is much more efficient way of
removing heat from the OSCD. This method also re-
duces the cooling load on the internal cooling coil. In
the past, YORK developed direct liquid cooling for the
inverter IGBT modules, but today York is direct liquid
cooling the rectifier, inverter, and the output filter in-
ductor.
The cooling system for the OSCD is greatly modified
to improve serviceability of the power electronics. Re-
pair of the power electronics no longer requires access
to the back of the drive except to drain the cooling sys-
tem. Also the use of a shell and tube heat exchanger is
standard on all models.
The OSCD can now be configured for many different
input voltage levels. Lower input voltages may de-rate
the input power rating of the OSCD, but the OSCD
will produce the same output voltage and will use the
same motor.
The harmonic filter is no longer an option, and the
function of the harmonic filter is included in a new
rectifier module. This type of arrangement for the rec-
tifier no longer requires a separate power unit for the
harmonic filter. Also this rectifier is part of the power
unit for the inverter, thus reducing the number of parts
required and increasing reliability.
The new OSCD control system allows for high speed
operation of the compressor motor. This improvement
eliminates the need for a gear system between the com-
pressor motor and the compressor. Without a gear sys-
tem reliability and efficiency are improved.
The new power unit consists of a newly designed bus
capacitor, new light weight plastic cooling blocks, new
IGBT gate driver design, new rectifier IGBT module,
and the cooling system is connected to the front of the
power unit for reduce service cost.
The new bus capacitor is the core of the power unit.
The new capacitor is made of a material that is much
more robust and has a longer lifetime than bus capaci-
tors commonly used in the past. Also, this capacitor
contains all of the hardware required to mount all of
the other parts to the power unit.
The harmonic filter operation is now part of the input
to the OSCD. This feature is no longer an option when
the OSCD is used with the YMC
2
chiller.
New special plastic cooling blocks were designed for
this OSCD. These plastic cooling blocks provide a
SECTION 3 - VSD OPERATION